Fig. 1.

A-B. SARS-CoV-2 QMRA schematic for respiratory event (coughing versus breathing) and infection risk through aerosol, close contact (1–3 m, droplet and aerosol), and fomite-mediated transmission assuming no risk mitigation interventions. A. This conceptual model depicts the three transmission pathways (close contact [droplet and aerosol], aerosol, and fomite-mediated) within a representative food manufacturing facility, initiating with a single infected worker either coughing (symptomatic) or breathing (asymptomatic) to generate virus-containing respiratory droplets and aerosols. Droplets fall rapidly due to gravitational forces and were categorized by size and distance traveled from source based on empirical experiments and modeling studies (Bourouiba et al., 2014; Wei & Li, 2015): <1 m (50–750 μm), 1–2 m (50–100 μm), and 2–3 m (50–60 μm). Aerosols were defined as <50 μm in diameter with the ability to become aerosolized and remain suspended in the air throughout the entire facility space. B. Infection risk from combined transmission events (aerosol, droplet, fomite-mediated) in association with exposure to an infected worker (coughing) over a period of 1–8 h and as a function of distance. Results are presented as the median risk values with 5th and 95th percentile bars.